Li-Na Xiao

New compounds constructed from polyoxometalates and transition metal coordination complexes with lower positive charge

Five new hybrid compounds constructed from polyoxometalates and transition metal coordination complexes with lower positive charge: [PW11CuO39][Cu(bpy)2]5 (1), [BW12O40][Cu(bpy)2]5 (2) [BW12O40][Cu(Phen)2]3[Cu(Phen)(H2O)]2·2H2O (3), [SiW12O40][Cu(bpy)2]4 (4) and [PW12O40][Cu(bpy)2]4 (5) have been prepared and characterized by IR, UV-Vis, XPS, XRD and single crystal X-ray diffraction analyses. The packing motif of the [Cu(bpy)2]+ copper coordination complexes in compound 1 exhibits square supramolecular channels running along the a axis, which are then filled by the [PW11CuO39]5− ions. Compound 2 is isomorphours with compound 1. Compound 3 contains a novel 2-D supramolecular layer structure constructed from [Cu(Phen)2]+ copper coordination complexes through π⋯π interactions. The packing motif of the [Cu(bpy)2]+ copper coordination complexes in compound 4 exhibits a supramolecular channel which is different from compound 1. Compound 5 is isomorphours with compound 4.

Secondary organic moiety templated organic–inorganic polyoxometalate-based frameworks

Four new organic–inorganic hybrid compounds, namely, [Cu3(4,4′-bpy)3][HSiW12O40]·(C3H4N2) (1), [Cu3(4,4′-bpy)3][PMo12O40]·(C5H6N2)·0.5H2O (2), [Cu2(4,4′-bpy)2][HPMo12O40]·(C5H6N2) (3) and [Cu(Phen)(4,4′-bpy)(H2O)]2[PW12O40]·(4,4′-bpy) (4) (C3H4N2 = imidazole, C5H6N2 = 2-aminopyridine, bpy = bipyridine, Phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-vis, powder XRD, cyclic voltammetry analysis, photoluminescence analysis, elemental analyses and single crystal X-ray diffraction. The four compounds represent new examples of secondary organic moiety templated frameworks constructed from Keggin polyanions, metal ions and organic ligands. Compounds 1 and 2 present 3-D framework structures; compound 3 exhibits a 1-D ladder-like structure and compound 4 shows a 2-D layered framework structure. It is noted that the packing structures of compounds 1 and 2 are almost identical; however, the crystal space groups and cell parameters of the two are thoroughly different. Such a phenomenon has also been observed between compound 3 and a compound recently reported by us. Compound 4 is the first framework structure constructed from polyoxometalates, metal ions and mixed organic ligands. In addition, all the four frameworks are combined with dissociated organic moieties as templates.

The design, syntheses and characterization of a series of hybrids based on polyoxometalates and metal complexes

Six new hybrid compounds based on polyoxometalates and transition metal complexes, [SiW12O40][Ag4(2,2′-bpy)4(4,4′-bpy)3]·2H2O (1), [SiMo12O40][Cu(2,2′-bpy)(H4,4′-bpy)2(H2O)][H4,4-bpy] (2), [PMo12V2O42][Cd2(Phen)2(4,4′-bpy)2(H2O)2(C2O4)]·2H2O (3), [PMo12V2O42][Cu2(4,4′-bpy)2][Cu2(Phen)(4,4′-bpy)2]·3H2O (4), [SiMo12V2O42][Cu2(Phen)2(4,4′-bpy)]2 (5) and [GeMo12V2O42][Cu2(Phen)2(4,4′-bpy)]2 (6) (bpy = bipyridine, Phen = phenanthroline), have been synthesized and characterized. Compound 1 contains a discrete tetranuclear silver-2,2′-bpy-4,4′-bpy complex; compound 2 is the first example where the polyoxometalate supports a metal–aqua–2,2′-bpy-4,4′-bpy complex; it should be noted that the complex contains a 2,2′-bpy and two 4,4′-bpy ligands; compound 3 is the first hybrid compound based on polyoxometalates and metal–aqua–4,4′-bpy–oxalic–phenanthroline complexes; and compound 4 is a novel hybrid compound based on polyoxometalates, extended metal–4,4′-bpy complexes and extended metal–4,4′-bpy–phenanthroline complexes together. Compounds 5 and 6 are isomorphous and isostructural; both exhibit a supramolecular structure constructed from bicapped Keggin POMs and metal–4,4′-bpy–phenanthroline complexes.

The syntheses, structures and characterizations of a series of frameworks constructed from polyoxometalates, metals and organic units

Five hybrid compounds constructed from polyoxometalates, transition metals and organic ligands [Ni2(4,4′-bpy)5(H2O)2][HBW12O40]·5H2O (1), [Ni2(4,4′-bpy)5(Cl)2][H2SiW12O40]·3H2O (2), [Ni2(4,4′-bpy)5(Br)2][H2SiW12O40]·3H2O (3), [SiW12O40]3[Cu2(4,4′-bpy)7]·(H24,4′-bpy)2·4H3O·2H2O (4) and [SiW12O40]3[Cd2(4,4′-bpy)7]·(H24,4′-bpy)2·4H3O·2H2O (5) have been prepared and characterized by IR, UV-vis, XPS, XRD, TG, circular dichroism, second order nonlinear optical (NLO) measurements, photoluminescent measurements and single crystal X-ray diffraction analyses. The X-ray diffraction analyses reveal that the five compounds all exhibit novel framework structures constructed from polyoxometalates, transition metals and organic ligands. The compounds 1, 2, and 3 are isomorphous and compounds 4 and 5 are isomorphous, too. There are two main differences among the first three compounds. The first difference of the three is the central atom of the Keggin ions: it is B atom for compound 1, and Si atom for compounds 2 and 3. The second difference of the three is the monodentate ligand coordinating to the Ni ions: it is water molecule for compound 1, chloride ion for compound 2 and bromide ion for compound 3. The difference between compounds 4 and 5 is the transition metal centre of the frameworks. In addition, compounds 4 and 5 are the first examples of compounds containing both Keggin ion and pseudo-Keggin ion.

Three novel supramolecular hybrid compounds based on keggin polytungstates

Three novel supramolecular compounds [PWVI10.5WV1.5O40][Cu(2, 2′-bpy)2]4.5 (1), [CuI(Phen)2]4[CuI5Cl4(Phen)4][PWVI10WV2O40]2·4H2O(2) and [CuI(Phen)2]4[CuI5Cl4(Phen)4][BWVI12O40]2·2H2O(3) (bpy = bipyridine, Phen = 1,10-Phenanthroline) have been synthesized and characterized by IR, UV-Vis, TG, XRD, elemental analyses and single crystal X-ray diffraction analyses. Compound 1 is the first example of a hybrid compound which is constructed from polyoxometalates and supramolecular noncovalent coordination cages. Both compounds 2 and 3 are constructed from two different types of building blocks: polyoxometalates and metal halide fragments.

New compounds based on polyoxometalates and metal halide clusters

Seven new compounds based on polyoxometalates and metal halide clusters have been synthesized and characterized by IR, XPS, UV-vis, XRD, elemental analyses and single crystal X-ray diffraction analyses. Compounds 1, 2, 3 and 4 are hybrids based on polyoxometalates and ennea-nuclear metal halide clusters, which are isomorphous to the compounds we reported recently. Compounds 5–7 are new examples of hybrids based on polyoxometalates and metal halide clusters, of which compounds 5 and 6 are the first examples of hybrids based on polyoxometalates and a new kind of hepta-nuclear metal halide cluster and compound 7 is the first example of hybrid based on polyoxometalates and octakaideca-nuclear metal halide clusters. In addition, compounds 2, 3 and 4 are the first examples of hybrids based on polyoxometalates and metal bromide clusters, and compounds 5 and 6 are the second examples of hybrids based on polyoxometalates and metal iodine clusters. Furthermore, compound 7 is the first example of compounds based on POMs and metal halide extended structures.

Two supramolecular structures constructed from Keggin-type polyoxometalates and 4,4′-bipyridine

Two supramolecular compounds based on Keggin-type polyoxometalates (POMs), (4,4′-H2bpy)(4,4′-Hbpy)[PMo12O40] (1) and (4,4′-H2bpy)(4,4′-Hbpy)2[SiW12O40] · 4H2O (2), have been synthesized hydrothermally and characterized by elemental analyses, IR, UV-Vis, XPS spectra, thermogravimetric analyses, and single-crystal X-ray diffraction analyses. The two compounds consist of 4,4′-bipyridine (4,4′-bpy) ligands and different Keggin-type POMs which are [PMo12O40]3− for 1 and [SiW12O40]4− for 2. There are hydrogen-bonding interactions between the POMs, 4,4′-bipyridine, and/or water in 1 and 2. In addition, 2 contains an uncommon (H2O)2 water cluster.

The synthesis and characterization of three organic–inorganic hybrids based on different transition metal complexes and {As8V14O42(H2O)} clusters

Three new arsenic–vanadium compounds, [As8V14O42(H2O)][Cu(2,2′-bpy)2]4 (1) [As8V14O42(H2O)][Cu(1,10-Phen)2]4 (2) and [As8V14O42(H2O)][Ni(Biim)3]2·6H2O (3) (2,2′-bpy = 2,2′-bipyridine, 1,10-Phen = 1,10-phenanthroline and Biim = 2,2′-biimidazole), have been prepared hydrothermally and characterized by IR, UV-Vis, XRD, XPS, and single-crystal X-ray diffraction analyses. X-ray crystallographic studies showed that compounds 1–3 are all based on the cluster anion [As8V14O42(H2O)]4−. However, the crystal structures of the three are thoroughly different. It is obvious that the transition metal complex building blocks are the vital factor for the packing structures of the three. We carefully discussed the influence of transition metal complex building blocks on the crystal structures. Also we analyzed the catalytic properties of the compounds and discussed the influence of the crystal structures of transition metal complexes on the catalytic properties.

pH-controlled assembly of two new supramolecular hybrid compounds based on Keggin polyoxotungstates

Two supramolecular compounds based on Keggin polyoxotungstates, (4,4′-H2bpy){[Cu(4,4′-bpy)]2[SiW12O40]} (1) and (4,4′-H2bpy)2[SiW12O40]·2H2O (2) have been synthesized and characterized by elemental analyses, IR, UV, XPS spectra, TG analyses, and single crystal X-ray diffraction analyses. Compound 1 exhibits an infinite 1-D ladder like structure, which is further interconnected into a 3-D supramolecular framework via hydrogen bonding interactions. Compound 2 contains 4,4′-bipyridine (4,4′-bpy), pseudo-Keggin polyoxoanions [SiW12O40]4−, and water molecules. Polyoxoanions together with water molecules in 2 construct a 3-D inorganic supramolecular network through O···O and O···Ow(1) interactions. The electrochemical behaviors and photocatalytic properties of 1 and 2 have been investigated.

Two new halide-containing polyoxometalate-based compounds

Two new compounds, [CuCl(Phen)(H2O)][PW12O40][4,4′-H2bpy]·1.5H2O (1) and [Cd2(Phen)4Cl2][HPMo12O40](4,4′-bpy) (2) (bpy = bipyridine, Phen = phenanthroline), have been hydrothermally prepared and characterized by IR, UV–vis, XPS, XRD, elemental analysis, cyclic voltammetry analysis, and single-crystal X-ray diffraction analysis. Compound 1 exhibits a 1-D chain structure constructed from polyoxometalates (POMs) and transition metal complexes, whereas 2 presents a supramolecular structure constructed from POMs, metal halide clusters, and organic ligands. Graphical Abstract